1. Field of the Invention
The present invention generally relates to an apparatus for illuminating coded information symbols. More particularly, the present invention relates to a high speed imaging apparatus for CCD based scanners.
2. Description of Prior Art
There are many difficulties associated with imaging objects or bar code symbols and other machine readable symbologies on packaging. Erroneous imaging of a human or machine readable symbology may be the result of poor printing of the symbology on a label or extraneous markings or contaminants located on the label. However, erroneous imaging is often the results of poor lighting conditions. Proper illumination is one of the most important requirements for any machine imaging system.
The illumination of an object or a label is particularly critical for high speed scanning systems that employ CCD detectors. As is well known by those skilled in the art, the ability of CCD scanning systems to accurately detect an object depends upon the amount of light that is reflected from the region of interest onto the CCD detector. The amount of light detected by the CCD detector is a function of both the integration period and the intensity of illumination.
Many current imaging systems in the material handling field include variable speed conveyors, wherein the conveyor speed varies with the volume of packages handled by the system. If a low intensity illumination level is selected for low speed conveyor operation, the same illumination level may be insufficient for accurate imaging when the conveyor speed is increased. If a high intensity illumination level is selected, the light may saturate the CCD detector when the conveyor is operating at low speeds.
High intensity illumination sources have also been known to generate tremendous amounts of heat, thus creating xe2x80x9cwave distortionsxe2x80x9d which may inhibit the ability of a CCD detector based system to accurately resolve the image. Additionally, the high intensity sources create an annoyance and even a safety hazard to nearby operators.
Accordingly, there exists a need for an illumination assembly which provides the desired illumination for operation of a conveyor at any speed.
The present invention is a high speed imaging apparatus used for CCD based image acquisition systems. The apparatus comprises a housing having separate compartments which complement modular assemblies installed therein. A decoder compartment houses a CCD camera head unit and components associated with locating and detecting and decoding an image. An optics compartment houses the mirrors and associated optics for reflecting the image onto the CCD detector. A lighting compartment includes high intensity lamps and the associated components for illuminating the object to be imaged. The lighting compartment includes a heat management system which removes the heat from the high intensity lamps and prevents heat from migrating to other compartments within the housing.
Accordingly, it is an object of the invention to provide an illumination assembly which provides the optimum amount of illumination according to the demands placed upon the system.
It is a further object of the invention to provide a high speed imaging apparatus with an effective heat management system.
Other objects and advantages will become apparent to those skilled in the art after reading the detailed description of a presently preferred embodiment.